Method and device for locating hole center

ABSTRACT

A device locates an apparatus to the center of a hole in a structure. The device includes a hub adapted to have the apparatus mounted thereon and a plurality of locator elements spaced around the hub which extend at least partially into the hole. Means coupled with the locator elements and the hub are used to displace the locator elements outwardly into engagement with the edges of the structure and to move the hub into axial alignment with the center of the hole.

TECHNICAL FIELD

This disclosure generally relates to tool fixtures, and deals moreparticularly with a method and device for locating a tool to the centerof a workpiece hole.

BACKGROUND

It is sometimes necessary to locate a working axis of a tool such as aninspection device or a drill at the center of the hole in a workpiece.In a production environment it may be necessary to accurately locate thehole center in each of a series of substantially identical parts inorder to take into account slight differences in hole sizes due tomanufacturing tolerances.

Devices exist for locating the center of a hole, but each may havedisadvantages. For example, an expanding mandrel may be used to locate ahole center, however expandable mandrels sometimes remain in theirexpanded position after repeated use and may require rework in order torender them suitable for reuse. Other available centering devices mayprovide inconsistent results in locating the center of the same sizedholes in substantially identical parts, while other devices may be toolarge or bulky for some applications.

Accordingly, there is a need for a method and device for locatingapparatus such as a tool to the center of a hole which is relativelysimple, rapid, accurate and provides consistent results.

SUMMARY

The disclosed embodiments provide a method and device for locatingapparatus to the center of a hole that provide consistent results and iseasy to use. When placed over a hole and actuated, the deviceself-adjusts to locate an axis of the apparatus to the center of thehole. The device is relatively simple in construction and may permit awide range of equipment or apparatus such as inspection equipment ordrills to be mounted directly on the device so as to locate and hold theequipment at the center of the hole while a machining, inspection orsimilar operation is performed.

According to one disclosed embodiment, a device is provided for locatingan apparatus to the center of a hole in a structure. The device includesa hub adapted to have the apparatus mounted thereon and a plurality oflocator elements spaced around the hub and extending at least partiallyinto the hole. Means are provided for displacing the locator elementsoutwardly into engagement with the edges of the structure and for movingthe hub into axial alignment with the center of the hole. The hub mayinclude a plurality of ramps engaging the locator elements and spacedaround the periphery thereof. The displacing means may include springsthat move the locator elements respectively along the ramps, therebycamming the locator elements outwardly into engagement with thestructure.

According to another disclosed embodiment, a device is provided forlocating an apparatus to a center of a hole in a structure. The deviceincludes a hub having a centerline and is adapted to have the apparatusmounted thereon. A ring surrounds the hub and is adapted to be placed onthe structure, overlying the hole. The device further includes anexpandable locator assembly mounted between the hub and the ring whichincludes locator elements extending into the hole. The locator elementsare biased to expand into engagement with the structure to move the huband bring the centerline of the hub into substantial alignment with thecenterline of the hole. Rotation of the ring relative to the hub drawsthe locator elements inwardly away from the structure, allowing thedevice to be removed from the structure after use.

According to another embodiment, a method is provided of locating anapparatus to a center of a hole in a structure. The method includesplacing the apparatus on a hub having a centerline and positioning thehub over the hole. Locator elements are placed in the hole, and are thenexpanded outwardly into engagement with the edges of the structuresurrounding the hole. Expansion of the locator elements into engagementwith the edges of the structure is used to move the hub to the center ofthe hole and bring the hub centerline into alignment with the holecenter.

The disclosed embodiments satisfy the need for a method and device forlocating apparatus to the center of a hole which is relatively simple,provides consistent, repeatable results and is easy to use.

BRIEF DESCRIPTION OF THE ILLUSTRATIONS

FIG. 1 is an illustration of a functional block diagram of a device forlocating the center of the hole.

FIG. 2 is an illustration of an isometric view showing the top side ofone embodiment of the device, the position of an apparatus that may bemounted on the device being shown in the phantom.

FIG. 3 is an illustration of an isometric view of the bottom side of thedevice shown in FIG. 2.

FIG. 4 is an illustration of an isometric view of a structure having ahole whose center may be located by the device shown in FIGS. 2 and 3.

FIG. 5 is an illustration of the bottom side of the structure shown inFIG. 4 and depicting the device having been placed on the structure anddisplaced to locate to the hole center.

FIG. 6 is an illustration of an isometric view of the ring forming partof the device of FIGS. 2 and 3.

FIG. 7 is an illustration of an isometric view of the roller spragueforming part of the device shown in FIGS. 2 and 3.

FIG. 8 is an illustration of an isometric view of the hub forming partof the device shown in FIGS. 2 and 3.

FIG. 9 is an illustration of an isometric view of the device in itsretracted position.

FIG. 10 is an illustration similar to FIG. 9, but showing the device inits expanded position.

FIGS. 11 and 12 are illustrations of diagrams useful in explaining themovement of the locator elements.

FIGS. 13 and 14 are illustrations of diagrams showing movement of thelocator elements into engagement with the structure and shifting of thedevice to align the centerline of the device with the hole center.

FIG. 15 is an illustration of a flow diagram showing the steps of amethod of locating apparatus to the center of a hole.

FIG. 16 is an illustration of a flow diagram of aircraft production andservice methodology.

FIG. 17 is an illustration of a block diagram of an aircraft.

DETAILED DESCRIPTION

Referring first to FIG. 1, the disclosed embodiments generally relate toa centering device 20 that may be used to locate an apparatus 22 to thecenter (not shown) of a hole 24 in a workpiece 26. The centering device20 includes a hub 28 upon which the apparatus 22 may be mounted. The hub28 includes a plurality of ramps 30 on the outer periphery thereof.Locator elements 32 bear against ramps 30 and are cammed outwardly intoengagement with the workpiece 26 by springs 50. The outward displacementof the locator elements 32 into engagement with the workpiece 26 movesthe hub 28 to locate the apparatus 22 at the center (not shown) of thehole 24. Rotation of an outer ring 34 forming part of the device 20overcomes the force of the springs 50 to retract the locator elements 32and allow removal of the device 20 from the structure after a centeringoperation has been performed.

Referring now also to FIGS. 2-8, the device 20 broadly includes anouter, circular ring 34, a central hub and a roller sprague 36 formingan expandable locator assembly 45 (FIG. 7) that couples the ring 34 withthe hub 28. As best seen in FIGS. 2, 3 and 6, the ring 34 includes apair of diametrically opposed handles 34 a which may be used to rotatethe ring 34 relative to the hub 28 and retract the locator assembly 45,as will be described below in more detail. Interior wall 34 b of thering 34 includes a plurality of arcuately shaped pockets 50. Althoughnot shown in the drawings, a ring shaped cover may be secured to thering 34 in order to protectively cover the roller sprague 36 and assistin holding the assembled internal parts together.

As best seen in FIG. 8, the hub 28 includes a central cylindricalopening 28 a therein which is concentric with both the central axis 40of the hub 28 and the ring 34. The hub 28 may also include any number ofthrough holes 28 b that may be used to mount an apparatus 22 (see FIG.2) on the hub 28 in order to locate the apparatus 22 to the central axis40 of the hub 28. As used throughout this description, “axis” and“centerline” will be used interchangeably. In the illustrated example,the hole 24 may possess one or more irregularities 27 but includes edges26 b that define a generally circular opening 24, the center of which isdesignated by the numeral 24 a and may sometimes also be referred toherein as centerline 24 a.

Returning now to FIG. 8, the hub 28 includes a plurality of rampsurfaces 30 arranged essentially end-to-end around the periphery of thehub 28. The ramp surfaces 30 are concentric about the central axis 40 ofthe hub 28. The upper and lower faces 31, 33 (see FIGS. 2 and 3) includea plurality of circumferentially spaced recesses 28 c immediatelyadjacent the ramp surfaces 30, as shown in FIG. 8.

The ring 34 and hub 28 may be formed of any suitable materials using avariety of known manufacturing techniques. Generally, the ring 34 andhub 28 may be formed of rigid materials such as metal or composites.

Referring particularly to FIG. 7, as previously mentioned, the rollersprague 36 forms an expandable locator assembly 45 comprising aplurality of cage sections 38, a plurality of the locator elements 32and a plurality of springs 50 respectively within the cage sections 38.The cage sections 38 are arranged in end-to-end relationship to eachother forming a circular configuration. Each of the cage sections 38 isgenerally U-shaped in cross section and includes a pair of fingers 38 awhich are adapted to be received within the recesses 28 c in the hub 28(see FIG. 8). In one embodiment, the cage sections 38 may be separatefrom each other, while in other embodiments, they may be joined togetherat their ends. A plurality of the locator elements 32 are respectivelymovably disposed within the cage sections 38 and are biased toward oneend of the cage sections 38 by means of the springs 50 which aregenerally Z-shaped in cross section. The cage sections 38 may be formedof any suitable material, such as metal. The cage sections 38 functionto retain and guide the movement of the locator elements 32 along theramp surfaces 30. In the illustrated example, the locator elements 32are generally cylindrical and may be hereinafter sometimes referred toas rollers 32. As best seen in FIGS. 3 and 5, the rollers 32 extend downbelow the bottom face 52 of the ring 34, and into the hole 24 when thedevice 20 is placed on the top surface 26 c of the structure 26 (FIG.4).

Referring particularly to FIGS. 2 and 3, the cage segments 36 aresupported on the hub 28 by the fingers 38 a. Each of the rollers 32bears against a corresponding ramp surface 30 as well as an arcuatepocket 50 in the ring 34. As shown in FIGS. 2, 3 and 7, the springs 50bear against the rollers 32 and bias the rollers 32 to move toward theupper end of the ramp surfaces 30, corresponding to a counter-clockwisedirection as viewed in FIG. 2. The biasing influence exerted by thesprings 50 is transferred through the rollers 32 to the ring 34 whichreacts the spring force. Thus, the springs 50 normally bias the rollers32 to move up the ramp surfaces 30, thereby caroming the rollers 32radially outward. However, a sufficient rotational force applied to thering 34 in a clockwise-direction (as viewed in FIG. 2) overcomes thebiasing force of the springs 50, causing the ring 34 to rotate relativeto the hub 28 and forcing the rollers 32 to move down the ramp surfaces30. As the rollers 32 move down the ramp surfaces 30, the rollers 32 caminwardly and retract toward the centerline of the hub 28.

Referring now to FIGS. 4, 5, 9 and 10, in use, the ring is 34 firstrotated relative to the hub 28 by moving the arms 34 a clockwise (FIG.2), causing the rollers 32 to move to their retracted positions. Duringthis rotation of the ring 34, the hub 28 is restrained against rotationeither by directly holding the hub 28 or by placing a key or similarwrench (not shown) into one or more openings in the hub 28, such as thethrough holes 28 b in order to restrain the hub 28 against rotation asthe ring 34 is rotated. With the rollers 32 retracted, the device 20 maythen be placed on the surface 26 c (FIG. 4) of a structure 26 with therollers 32 extending through the opening 24. Next, the rotational forcemay be removed from the ring 34, thereby releasing the hub 28 and ring34 to rotate relative to the ring 34 under the biasing influence exertedby the springs 50. As the ring 34 is released, the springs 50 cause therollers 32 move up the corresponding ramp surfaces 30. Because the rampsurfaces 30 are inclined relative to a tangent (not shown) around theperiphery of the hub 28, the rollers 32 move radially outward in acamming action, in unison with each other. FIG. 10 illustrates the fullyexpanded state of the device 20 in which the rollers 32 have beendisplaced to the upper end of the ramp surfaces 30.

Attention is now directed to FIGS. 11 and 13 which illustrate theretracted position of the rollers 32, when the ring 34 has beeninitially rotated while the hub 28 is retrained, thereby reading thedevice 20 for a centering operation. The rollers 32 are regularly spacedaround a circle 56 which expands and contracts with the camming actionproduced by rotation of the ring 34 relative to the hub 28. The outwarddisplacement of the rollers 32 is indicated by the arrows 58 in FIG. 11resulting from the camming action produced by the biasing force of thesprings 50. During this camming action, the rollers 32 expand outwardlyuntil one or more of the rollers 32 engage inside edges 26 b of thestructure 26 which surround the hole 24. The structure 24 reacts theforce applied by the rollers 32 which have contacted the edges 26 b sothat continued outward displacement of the rollers 32 causes the hub 28,and thus the entire device 20 to be displaced toward the center 24 a ofthe hole 24. FIG. 11 illustrates the centerline 40 of the hub 28 beingdisplaced in the direction shown by the arrow 60 until it is alignedwith the center 24 a of the hole 24.

FIGS. 12 and 14 illustrate the position of the rollers 32 when they havebeen fully expanded and brought into contact with the edges 26 b of thestructure 26, causing displacement of the centerline 40 of the hub 28.As can be seen in these two figures, the centerline 40 of the hub 28 hasbeen brought into alignment with the center 24 a of the hole 24, suchthat the centerline 40 of the hub 28 is substantially coaxial with thecenterline 24 a of the hole 24.

Attention is now directed to FIG. 15 which illustrates the overall stepsof a method of locating an apparatus 22 to the center 24 a of astructure 26. Beginning at 66, a desired apparatus 22 is placed ormounted on the hub 28 such that a working axis or centerline (not shown)on the apparatus 22 is aligned with the centerline 40 of the hub 28.Next, at 68, the hub 28 is positioned over the hole 24, and the locatorelements 32 are retracted inwardly by rotating the ring 34 relative tothe hub 28. With the locator elements 32 retracted, they may be insertedinto the hole 24 and the device 20 may be rested on the surface 26 c ofthe structure 26, as shown at 70. Then, at 72, the ring 34 is released,allowing the springs 50 expand the locator elements 32 until they moveinto engagement with the structure 24. Finally, as shown at step 74, thelocator elements 32 are used to displace the hub 28 and bring thecenters 24 a, 40 of the hole 24 and hub 28, respectively into alignmentwith each other.

After the apparatus 22 has completed a locating operation, the ring 34(FIG. 2) is rotated in a clockwise direction 46 shown in FIG. 9 relativeto the hub 28, thereby overcoming the biasing influence of the springs50 (FIG. 3) and causing the rollers 32 to retract inwardly so as toclear the edges 26 b of the structure 26. With the rollers 32 clear ofthe edges 26 b, the device 20 may be removed from the structure 26.

Embodiments of the disclosure may find use in a variety of potentialapplications, particularly in the transportation industry, including forexample, aerospace, marine and automotive applications. Thus, referringnow to FIGS. 16 and 17, embodiments of the disclosure may be used in thecontext of an aircraft manufacturing and service method 80 as shown inFIG. 16 and an aircraft 82 as shown in FIG. 17. During pre-production,exemplary method 80 may include specification and design 84 of theaircraft 82 and material procurement 86. During production, componentand subassembly manufacturing 88 and system integration 90 of theaircraft 82 takes place. The disclosed device 20 may be used to locatevarious tools and fixtures to the centers of holes formed in componentsand subassemblies during these production processes. Thereafter, theaircraft 82 may go through certification and delivery 92 in order to beplaced in service 94. While in service by a customer, the aircraft 82 isscheduled for routine maintenance and service 96 (which may also includemodification, reconfiguration, refurbishment, and so on). The disclosedmethod may be used to locate equipment to hole centerlines on componentsthat are installed during the maintenance and service 96.

Each of the processes of method 80 may be performed or carried out by asystem integrator, a third party, and/or an operator (e.g., a customer).For the purposes of this description, a system integrator may includewithout limitation any number of aircraft manufacturers and major-systemsubcontractors; a third party may include without limitation any numberof vendors, subcontractors, and suppliers; and an operator may be anairline, leasing company, military entity, service organization, and soon.

As shown in FIG. 17, the aircraft 82 produced by exemplary method 80 mayinclude an airframe 98 with a plurality of systems 100 and an interior102. The disclosed device may be used to locate equipment to holecenterlines on parts which form part of, or may be installed on theairframe 98. Examples of high-level systems 100 include one or more of apropulsion system 104, an electrical system 106, a hydraulic system 108,and an environmental system 110. Any number of other systems may beincluded. Although an aerospace example is shown, the principles of thedisclosure may be applied to other industries, such as the marine andautomotive industries.

The disclosed device and method may be employed to locate equipment tohole center of parts during any one or more of the stages of theproduction and service method 80. Also, one or more method embodiments,or a combination thereof may be utilized during the production stages 88and 90, for example, by substantially expediting assembly of or reducingthe cost of an aircraft 82. Similarly, the disclosed device and methodmay be used to locate equipment to the center of a hole in a part thatare utilized while the aircraft 82 is in service 94.

Although the embodiments of this disclosure have been described withrespect to certain exemplary embodiments, it is to be understood thatthe specific embodiments are for purposes of illustration and notlimitation, as other variations will occur to those of skill in the art.

What is claimed:
 1. A device for locating an apparatus to a center of ahole in a structure, comprising: a hub adapted to have the apparatusmounted thereon; a plurality of locator elements spaced around the huband extending at least partially into the hole; and, means coupled withthe locator elements and the hub for displacing the locator elementsoutwardly into engagement with the edges of the structure and for movingthe hub into substantial alignment with the center of the hole.
 2. Thedevice of claim 1, wherein: the hub includes a plurality of rampsurfaces engaging the locator elements and spaced around the peripheryof the hub, and the displacing means includes a plurality of springs forbiasing the locator elements to move respectively move along the rampsurfaces.
 3. The device of claim 2, wherein each of the locator elementsis a roller.
 4. The device of claim 2, wherein the ring includes aplurality of pockets in the periphery thereof for respectively retainingthe locator elements therein.
 5. The device of claim 4, furthercomprising a plurality of cages between the hub and the ring forretaining the locator elements and for guiding the movement of thelocator elements along the ramp surfaces.
 6. The device of claim 2,wherein the hub and the ring are substantially concentric.
 7. The deviceof claim 2, wherein the locator elements are arranged at regularlyspaced intervals around a circle.
 8. The device of claim 2, wherein thelocator elements are arranged at regularly spaced intervals around acircle.
 9. A device for locating an apparatus to a center of a hole in astructure, comprising: a hub having a centerline and adapted to have theapparatus mounted thereon; a ring surrounding the hub and adapted to beplaced on the structure overlying the hole; and, an expandable locatorassembly mounted between the hub and the ring and including locatorelements extending into the hole, the locator elements being expandableinto engagement with the structure to move the hub and bring thecenterline of the hub into substantial alignment with the center of thehole.
 10. The device of claim 9, wherein: the ring is rotatable relativeto the hub, the expandable locator assembly includes a plurality ofsprings, and the locator elements are coupled with and driven to expandby the springs.
 11. The device of claim 9, wherein the expandablelocator assembly includes a roller sprague.
 12. The device of claim 9,wherein: the hub includes a plurality of ramp surfaces around theperiphery thereof, and the locator elements respectively bear againstand are movable along the ramp surfaces.
 13. The device of claim 12,wherein the expandable locator assembly includes a plurality of guidesbetween the hub and the ring for guiding the movement of the locatorelements along the ramps.
 14. The device of claim 9, wherein the hub andthe ring are substantially concentric.
 15. A method of locating anapparatus to a center of a hole in a structure, comprising: placing theapparatus on a hub; positioning the hub over the hole; placing locatorelements in the hole; expanding the locator elements outwardly intoengagement with edges of the structure surrounding the hole; and, usingthe expansion of the locator elements to move the hub to the center ofthe hole and bring the center of the hub into substantial alignment withthe center of the hole.
 16. The method of claim 15, wherein expandingthe locator elements includes camming the elements outwardly from thehub by moving the locator elements along ramped surfaces on the hub. 17.The method of claim 15, wherein expanding the locator elements includesusing springs to bias the locator elements outwardly from the hub andinto engagement with the structure.
 18. The method of claim 15, whereinexpanding the locator elements includes using a spring bias to cam thelocator elements outwardly along ramp surfaces.
 19. A method of locatingan apparatus to a center of a hole in a structure, comprising: mountingthe apparatus on a hub having a centerline; placing a ring on thestructure surrounding the hole; using the ring to support the hub overthe hole; placing locator elements in the hole, including retracting aset of locator elements inwardly by rotating the ring relative to thehub; expanding the locator elements outwardly into engagement with theof the structure surrounding the hole, including— using spring bias tocam the locator elements outwardly along ramped surfaces on the hub; andusing the expansion of the locator elements to move the hub and bringthe hub centerline into alignment with the center of the hole.
 20. Adevice for locating an apparatus to a center of a hole in a structure,comprising: a generally round hub having a central opening therethroughand a plurality of ramped surfaces spaced around the periphery thereof,the ramped surfaces being concentric about the central opening, the hubfurther including a plurality of circumferentially spaced recessestherein around the periphery thereof; a ring adapted to be placed on thestructure and surrounding the hub, the ring being rotatable relative tothe hub and supporting the hub over the hole, the ring including aplurality of circumferentially spaced pockets therein; and a rollersprague assembly mounted between the ring and the hub, the spragueassembly including— a plurality of cage segments arranged end-to-end ina circle, each of the cage segments having fingers respectively receivedin the recesses in the hub for retaining the cage segments on the hub, aroller within each of the cage segments, each of the rollers being heldin one of the pockets and bearing against one of the ramp surfaces, anda spring associated with each of the rollers for biasing the roller tomove in one direction along one of the ramp surfaces, the biasing forceapplied by the springs causing the rollers to cam outwardly along theramp surfaces into engagement with the structure and move the centerlineof the hub opening into substantial axial alignment with the center ofthe hole.